title: Association of IGF-I and IGFBP-3 with health care costs and hospitalization: results from a prospective observational study.
abstract: OBJECTIVE
  Previous cohort studies found robust associations of serum insulin-like growth factor I (IGF-I) and its main binding protein IGFBP-3 with increased morbidity or mortality. This study investigates the relationships between IGF-I and IGFBP-3 with health care costs and hospitalization in a general population and whether adding IGF-I or IGFBP-3 to a model of established health care predictors improves prediction.
  
  
  METHODS
  Data from a population-based cohort study of 3139 men and women in Germany, aged 20 to 80 years at baseline were used (median follow-up time: 5.0 years). Self-reported physician visits, length of hospital stay were used to estimate annual costs. IGF-I and IGFBP-3 were categorized at the 10th and 90th percentile, to indicate 'low', 'intermediate', and 'high' concentrations, respectively.
  
  
  RESULTS
  Total annual health care costs, with the major component of inpatient costs, and risk of hospitalization at baseline and follow-up were higher in subjects with low compared to intermediate IGF-I or IGFBP-3, after multivariable-adjustment. Subjects with low in contrast to intermediate IGF-I exhibited 30.6% higher annual total costs 5 years after baseline examination, corresponding to a difference in adjusted costs of EUR436.61.
  
  
  CONCLUSIONS
  Low IGF-I and IGFBP-3 independently predict future health care costs and hospitalization. IGF-I or IGFBP-3 might be useful to identify subjects with excess health care use. The predictive performance of cross-sectional and longitudinal models of total and inpatient costs were slightly improved by adding IGF-I or IGFBP-3 but the cost-effectiveness of inclusion into prediction models needs to be examined.
authors.affiliation: Institute for Community Medicine, University of Greifswald, Germany. sebastian.baumeister@uni-greifswald.de
authors.forename: Sebastian E
authors.initials: SE
authors.lastname: Baumeister
authors.forename: Nele
authors.initials: N
authors.lastname: Friedrich
authors.forename: Carsten Oliver
authors.initials: CO
authors.lastname: Schmidt
authors.forename: Henry
authors.initials: H
authors.lastname: Völzke
authors.forename: Matthias
authors.initials: M
authors.lastname: Nauck
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hoffmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Flessa
authors.forename: Paul
authors.initials: P
authors.lastname: Marschall
authors.forename: Henri
authors.initials: H
authors.lastname: Wallaschofski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D017048:Health Care Costs; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I